CHAPTER4 - BOARD OPERATION AND PROGRAMMING
BA +0: Read
Sntus/Srart
Convert
(Readl'\Mrire) .........44
BA + l: ReadA/D Data/UpdateDACOutputs
(Read/Write) ...........44
BA+2: Reset
(Write
Only).......... ...........44
BA+4: PPIPortA - Digital
VO
(ReadAMrire)
................ ...............4-5
BA + 5: PPI
Port
B- Channel8oard
Functions
Select
(Readflilrite) ..................4-5
BA+6:PPIPort
C- Digital
VO
(Readflilrire)
................ ................4-5
BA+7: 8255
PPI
ConrolWord
(Write
Only)........... .......................4-5
BA+8: SZl4TimerlCounrer0
(ReadAMrite) ...............4-7
BA+ 9: 8254Timer/CountorI (Read/lMri9 ...............4-7
BA+ l0: 8254Timer/Counr€r2(ReadAMrite) .............4-7
BA+ 11:
S254ConrolWord(WriteOnly)........... .......4-7
BA+ 12:D/AConverter1LSB:ADA1200
(Wrire
Only).......... ......4-g
BA+ 13:D/AConverter1MSB:ADAI200
(Wrire
Only)........... .........................4-g
BA+ 14:D/AConverter
2LSB:ADAI200
(Wrire
Only)
.......... ......4-g
BA+ 15:D/AConverter
2MSB:ADA12200
(Write
Only)........... .......................4-g
Clearing
andSettingBitsin
Initializing
Enabling
and
Disabling
the
Extemal
Trigger
..... ....................4-12
Enabling
and
Disabling
Intemrprs ......4-12
ConversionModes/Triggering
............ .....................4-12
Starting
anA/DConversion ..........,.....4-13
Monitoring
Conversion
Status
@MA Done
orEnd-of-Convert) ......................4-13
Reading
the
ConvertedData
............ ...4-13
Programming
thePacer
Clock
.................. ...............4-14
8259Programmable
Intemrpt
Controller .................4-16
Intemrpt
MaskRegister
(IMR).......... ......................4-16
End-of-Interrupt
(EOI)
Command ......4-16
What
Exactly
llappensWhen
an
Intemrpt
Occurs? .....................4-16
Using
IntemrptsinYour
Programs.......... ................4-16
Writing
an
Interrupt
Service
Routine(ISR) .............4-17
Saving
thestartup
Intemrpt
MaskRegister(IMR)and
Intemrpt
vector ..........4-tg
Restoring
the
Startup
IMR andInterrupt
Vector .....4-lg
Common
InterruptMistakes ...............4-19
Choosing
aDMA Channel ..................4-19
Allocating
a
DMABuffer ...................4-19
Calculating
the
Page
andOffset
of aBuffer ............4-20
Setting
theDMA PageRegister................... ............4-2t
The
DMA
DMA Single
Mask
Register ................4-Zz
Programming
the
DMA Controller .....4-23
Programming
the1200forDMA..... .,4-23
